/* -*- c++ -*- */
/*
 * Copyright 2004,2007,2008,2010,2012 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "fft_vcc_fftw.h"
#include <math.h>
#include <string.h>
#include <volk/volk.h>

namespace gr {
namespace fft {

fft_vcc::sptr fft_vcc::make(int fft_size,
                            bool forward,
                            const std::vector<float>& window,
                            bool shift,
                            int nthreads)
{
    return gnuradio::get_initial_sptr(
        new fft_vcc_fftw(fft_size, forward, window, shift, nthreads));
}

fft_vcc_fftw::fft_vcc_fftw(int fft_size,
                           bool forward,
                           const std::vector<float>& window,
                           bool shift,
                           int nthreads)
    : sync_block("fft_vcc_fftw",
                 io_signature::make(1, 1, fft_size * sizeof(gr_complex)),
                 io_signature::make(1, 1, fft_size * sizeof(gr_complex))),
      d_fft_size(fft_size),
      d_forward(forward),
      d_fft(fft_size, forward, nthreads),
      d_shift(shift)
{
    if (!set_window(window))
        throw std::runtime_error("fft_vcc: window not the same length as fft_size");
}

void fft_vcc_fftw::set_nthreads(int n) { d_fft.set_nthreads(n); }

int fft_vcc_fftw::nthreads() const { return d_fft.nthreads(); }

bool fft_vcc_fftw::set_window(const std::vector<float>& window)
{
    if (window.empty() || window.size() == d_fft_size) {
        d_window = window;
        return true;
    } else
        return false;
}

int fft_vcc_fftw::work(int noutput_items,
                       gr_vector_const_void_star& input_items,
                       gr_vector_void_star& output_items)
{
    const gr_complex* in = (const gr_complex*)input_items[0];
    gr_complex* out = (gr_complex*)output_items[0];

    unsigned int input_data_size = input_signature()->sizeof_stream_item(0);
    unsigned int output_data_size = output_signature()->sizeof_stream_item(0);

    int count = 0;

    while (count++ < noutput_items) {

        // copy input into optimally aligned buffer
        if (!d_window.empty()) {
            gr_complex* dst = d_fft.get_inbuf();
            if (!d_forward && d_shift) {
                unsigned int offset = d_fft_size / 2;
                int fft_m_offset = d_fft_size - offset;
                volk_32fc_32f_multiply_32fc(
                    &dst[fft_m_offset], &in[0], &d_window[0], offset);
                volk_32fc_32f_multiply_32fc(
                    &dst[0], &in[offset], &d_window[offset], d_fft_size - offset);
            } else {
                volk_32fc_32f_multiply_32fc(&dst[0], in, &d_window[0], d_fft_size);
            }
        } else {
            if (!d_forward && d_shift) { // apply an ifft shift on the data
                gr_complex* dst = d_fft.get_inbuf();
                unsigned int len = (unsigned int)(floor(
                    d_fft_size / 2.0)); // half length of complex array
                memcpy(&dst[0], &in[len], sizeof(gr_complex) * (d_fft_size - len));
                memcpy(&dst[d_fft_size - len], &in[0], sizeof(gr_complex) * len);
            } else {
                memcpy(d_fft.get_inbuf(), in, input_data_size);
            }
        }

        // compute the fft
        d_fft.execute();

        // copy result to our output
        if (d_forward && d_shift) { // apply a fft shift on the data
            unsigned int len = (unsigned int)(ceil(d_fft_size / 2.0));
            memcpy(&out[0],
                   &d_fft.get_outbuf()[len],
                   sizeof(gr_complex) * (d_fft_size - len));
            memcpy(
                &out[d_fft_size - len], &d_fft.get_outbuf()[0], sizeof(gr_complex) * len);
        } else {
            memcpy(out, d_fft.get_outbuf(), output_data_size);
        }

        in += d_fft_size;
        out += d_fft_size;
    }

    return noutput_items;
}

} /* namespace fft */
} /* namespace gr */
